What number am I ?
2006-11-26 13:17:21 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
29 = 1* 29 ............. NO *
28 = 2^2 * 7 ........... 2 + 2 + 7 = 11
27 = 3^3 ................. 3 + 3 + 3 = 9
26 = 2 * 13 ............. 2 + 13 = 15 ←This is it as primes cannot count
25 = 5^2 ................. 5 + 5 = 10
24 = 2^3 * 3 ........... 2 + 2 + 2 + 3 = 9
23 = 1 * 23 ............ NO *
22 = 2* 11 .............. 2 + 11 = 13
21 = 3 * 7 ............... 3 + 7 = 10
* Sum of its factors are 1 and itself but 1 in not a prime.
2006-11-26 13:26:40 · answer #1 · answered by Wal C 6 · 0⤊ 0⤋
27 because its prime and its digits sum is the greatest out of all the prime numbers from 20 to 30 which are only 23 and 27
2006-11-26 13:26:25 · answer #2 · answered by steve 2 · 0⤊ 0⤋
make a list
20 = 2•2•5, sum = 9
21 = 3•7, sum = 10
22 = 2•11, sum = 13
and so on. not hard at all.
2006-11-26 13:22:04 · answer #3 · answered by Philo 7 · 0⤊ 0⤋
26 = 2x13
2+13 =15
2006-11-26 13:22:21 · answer #4 · answered by Jimbo 5 · 0⤊ 0⤋